diff --git a/core/ext/image.ext.php b/core/ext/image.ext.php
index 9d22b763..98162f5e 100644
--- a/core/ext/image.ext.php
+++ b/core/ext/image.ext.php
@@ -100,7 +100,7 @@ class ImageIO extends Extension {
 		$h = $config->get_int("thumb_height");
 		$q = $config->get_int("thumb_quality");
 
-		exec("convert $inname -geometry {$w}x{$h} -quality {$q} $outname");
+		exec("convert {$inname}[0] -geometry {$w}x{$h} -quality {$q} jpg:$outname");
 
 		return true;
 	}
diff --git a/ext/regen_thumb/main.php b/ext/regen_thumb/main.php
index f8a6393b..55f65fa2 100644
--- a/ext/regen_thumb/main.php
+++ b/ext/regen_thumb/main.php
@@ -41,7 +41,7 @@ class RegenThumb extends Extension {
 		switch($program) {
 			case 'convert':
 				if(file_exists($f_thumb)) unlink($f_thumb);
-				exec("convert $f_image -geometry {$w}x{$h} -quality {$q} $f_thumb");
+				exec("convert {$f_image}[0] -geometry {$w}x{$h} -quality {$q} jpg:$f_thumb");
 				break;
 			case 'gd':
 				$this->make_thumb_gd($f_image, $f_thumb);